1. Field of the Invention
This invention relates to a removable pressure calibration module installed in a pressure sensitive fluid delivery nozzle. One embodiment relates to a system for fueling large vehicles.
2. Description of the Related Art
Large construction and mining vehicles are often equipped with a fueling system that allows the fuel tank to be filled from the bottom. This enables the fueling of the vehicle to take place from ground level as many of the vehicles of this type are extremely large. There are two types of fueling systems that allow fueling from the bottom of the tank. They both incorporate three common components: 1) a fueling nozzle that senses a pressure change in order to shut off, 2) a fueling receiver that is permanently attached to the fuel tank to which the nozzle attaches, and 3) a fuel vent that can sense when the fuel tank is filled and provide a pressure change that can be sensed by the nozzle. One system uses a vent that closes an exhaust port when the fuel tank is full allowing the tank itself to become pressurized by the incoming fuel. The fuel nozzle senses this pressure and shuts off at a pre-determined pressure level. The second type of system uses a vent that is attached by one or more hoses to the fuel receiver. When the tank is full, the vent provides a pressure change to one or more of the hoses which causes a valve in the fuel receiver to change position which in turn causes the fuel nozzle to shut off. In some systems, the same fuel nozzle can be used in conjunction with different combinations of vents and receivers to provide either a pressure operated system (tank is pressurized) or a non-pressurized system (the tank is not pressurized).
Most fuel nozzles of this type incorporate a pressure sensing device. Most fuel nozzles, in current use, incorporate either a spring biased piston or diaphragm to sense the change in back pressure of the fuel flowing through the nozzle. The change in back pressure causes the nozzle to shut off when the pressure reaches a pre-set pressure. The pressure is typically calibrated and pre-set by mounting the entire nozzle on specialized equipment in a repair shop. Moreover, the nature of its function subjects the pressure sensing component to a significantly greater rate of wear than the other parts of the nozzle.
Due to the extreme conditions of use, the nozzles typically require frequent rebuilding—often after every few months or even after every few weeks of operation. The entire nozzle must be returned to a rebuild center to be completely disassembled, reassembled with certain potentially new components, and tested as a unit on a fairly complex test stand. Only a few fully equipped rebuild sites exist. This requires that complete back up sets of these expensive nozzles be kept on hand at the mining and construction sites for use while a first set of nozzles is being rebuilt.
Additionally, some fueling systems physically restrict the diameter of the delivery end of the fueling nozzle. At one time, most nozzles incorporated a rubber bumper on the end of the fuel nozzle to provide physical protection from incidental damage when the nozzle was not in use. Because of the new diameter restrictions, many users remove the rubber bumpers in order to fit on the newer fuel receivers, thus removing an important damage prevention feature of the nozzles.
From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that allows the pressure sensing component to be removed and replaced modularly on site. Beneficially, such an apparatus, system, and method would also allow the end user to repair, set, and calibrate the module, obviating the need for use of a rebuild center. A need also exists for a related apparatus, system, and method to protect the end of the nozzle when the nozzle is not in use. Beneficially, such an apparatus, system, and method, would be adaptable to various diameter restrictions of the fuel receiver.